Discovery of non-explicit co-traveler networks is interesting. I'd read an article about co-traveler networks here: Inferring High Quality Co-Travel Networks,

Discovery of non-explicit co-traveler networks is interesting. I'd read an article about co-traveler networks here: Inferring High Quality Co-Travel Networks, 20 May, 2013: http://arxiv.org/abs/1305.4429 http://arxiv.org/abs/1305.4429 pdf here: http://arxiv.org/pdf/1305.4429.pdf http://arxiv.org/pdf/1305.4429.pdf